1. Field of the Invention
The present invention relates to an electric junction box and terminals used in the electric junction box. The electric junction box is used for a vehicle for electrically connecting a plurality of vehicle-mounted loads to a power source such as a battery mounted therein.
2. Description of the Related Art
Conventionally, as an electric junction box provided in a vehicle, one is generally known which is provided with a bus bar board in which each group of metallic bus bars and each of insulating plates are alternately laminated, and a vehicle-mounted power source (e.g., a battery) is connected to a multiplicity of vehicle-mounted loads (electrical apparatuses) through bus bar circuits formed by the bus bar board. Further, a mechanical relay block is incorporated in the bus bar board such that current between the vehicle-mounted power source and the loads can be subjected to on/off switching midway thereof, as required.
FIG. 13 illustrates an example of a structure for incorporating the mechanical relay into an electric junction box. In FIG. 13, a bus bar board 102 is accommodated within an insulated housing 101, and end portions of bus bars making up the bus bar board 102 are bent upward to form a plurality of tab terminals 103, relay terminals 105 being adapted to be fitted to the tab terminals 103. Meanwhile, a connector housing portion 104 for relay is integrally formed on the insulated housing 101 to project outward from its outer surface. A plurality of terminal accommodating chambers 104a, into which the tab terminals 103 and the relay terminals 105 are inserted from the reverse side (lower side in the drawing), are formed in the housing portion 104. Further, as terminals of a relay block 106 are inserted in the terminal accommodating chambers 104a, the terminals of the relay block 106 are connected to the tab terminals 103 through the relay terminals 105, and the relay block 106 is fitted to the outer surface of the insulated housing 101.
With the above-described conventional electric junction box, it is necessary to build the relay block 106 on the bus bar board 102, but since the relay block 106 is of a mechanical type and of large-current specifications in which the relay block 106 is directly connected to the vehicle-mounted battery, its structure is inevitably large in size.
Meanwhile, on the bus bar board 102 side, a space for presenting the relay block 106 is required in its appropriate portion, so that the area of the bus bar board 102 increases by that margin, and the structure becomes complex. Moreover, since it is necessary to raise the plurality of (three in the illustrated example) tab terminals 103 at mutually proximate positions from the bus bar board 102 in order to connect the relay block 106 to the board, it is necessary to design the layout having leeway so that the bus bars do not interfere with each other. In some cases, there arises a need to increase the number of laminations of the bus bars.
For the above-described reasons, with the conventional electric junction box, its compact size and simplification of its structure are considered difficult, and drastic measures for them have been important tasks.
Furthermore, with the above-described conventional structure, in a case where a change of the working current, i.e., a change of the relay capacity, is made in accordance with the grade and the like of the vehicle, the size of the relay block 106 also changes in correspondence with the change. For this reason, the intervals between the plurality of tab terminals 103 and their positions of formation for connection of the relay block 106 must be changed. Namely, with the above-described conventional structure, since the relay block 106 is interposed in the circuitry formed by the bus bar board 102, in the case where the relay block 106 having a different size is used in correspondence with a change of specifications and the like, a design change of the overall bus bar board 102 must be made in correspondence with the relay block 106, so that there is a drawback in that versatility is low.
By the way, another example of the electric junction box is also disclosed in JP-A-9-182251, in which circuits whose current values differ from each other are integrated on the same board.
In its configuration, circuits whose current values differ are formed in a pair of housings, and bus bars for large currents, covered wires for medium currents, and printed circuits for small currents are selectively used in correspondence with the current values of the circuits.
In the above-described configuration, since necessary and sufficient wiring materials can be adopted in correspondence with the current values, it is possible to form a very compact electric junction box.
In recent years, however, a configuration has come to be required in which the covered wires and the printed circuits are satisfactorily connected as the structure of electrical wiring. However, if the wiring materials are merely selected in correspondence with the current values, it has been difficult to satisfactorily connect the covered wires and the printed circuits.
In view of the above-described circumstances, an object of the invention is to provide an electric junction box which makes it possible to establish electrical connection between a power source and loads with a compact and simple structure and which excels in versatility.
Another object of the invention is to provide terminals which, in particular, make it possible to satisfactorily connect covered wires and printed circuits in adopting necessary and sufficient wiring materials in correspondence with current values, and an electric junction box using the same.
According to a first aspect of the invention, there is provided an electric junction box for a vehicle for connecting a plurality of vehicle-mounted loads to a power source mounted in a vehicle, comprising: a power distributing unit which has an input terminal connected to the power source and a plurality of output terminals and in which semiconductor switching devices are interposed between the output terminals and the input terminal; and a bus bar circuit unit which has metallic bus bars for forming circuits and insulating plates each laminated thereon and connects the output terminals of the power distributing unit to the plurality vehicle-mounted loads, wherein the power distributing unit and the bus bar circuit unit are incorporated in a common housing in a state in which some of the bus bars of the bus bar circuit unit and the output terminals of the power distributing unit are connected.
In accordance with the above-described construction, since the semiconductor switching devices of the power distributing unit connected to the bus bar circuit unit function as a relay block in the conventional electric junction box, not only can the relay block be omitted, but a terminal structure for attaching the relay block to the bus bar board can be omitted from the bus bar circuit unit, so that the construction of the bus bar circuit unit can be remarkably simplified. Moreover, the power distributing unit is arranged such that small semiconductor switching devices are interposed between the input terminal and the output terminals, so that the power distributing unit is provided with a compact and lightweight arrangement as compared with the mechanical relay block. Accordingly, the electric junction box in accordance with the invention is able to establish electrical contact between the power source and the loads with a compact and simple structure as compared with the conventional electric junction box.
In addition, with this electrical junction box, since the power distributing unit and the bus bar circuit unit are independent of each other, the following advantages are offered as compared with the conventional construction in which a relay block is present in the bus bar circuit unit.
(1) In a case where, for example, the semiconductor switching devices must be replaced in conjunction with a change of the working current or the like, a common bus bar circuit unit can be used if there is no change on the bus bar circuit unit side. Namely, depending on the contents of the change of specifications, a measure can be provided by the replacement of the power distributing unit alone without making a design change of the bus bar circuit unit.
(2) The semiconductor switching devices used in the power distributing unit are of a type in which the amount of heat generated is generally relatively high, and there are many cases in which radiation and cooling are required for it. Here, with the structure in which the relay block 106 is interposed in the bus bar circuit unit in the conventional manner, even if the relay block 106 is simply substituted by the semiconductor switching devices, it is extremely difficult to efficiently radiate to outside the housing the heat generated by the semiconductor switching devices which are disposed in a distributed manner in the bus bar circuit unit, and this has been a major obstacle to the introduction of the semiconductor switching devices. With the structure in accordance with the invention, however, since the semiconductor switching devices to be connected to the bus bar circuit unit are disposed in a concentrated manner in the power distributing unit which is independent of the bus bar circuit unit, the cooling processing of the semiconductor switching devices can be effected collectively in the power distributing unit.
Specifically, the arrangement provided is such that a radiating member connected to the semiconductor switching devices in such a manner as to be capable of transferring heat is disposed in the power distributing unit, and the power distributing unit is built is the housing such that the radiating member is exposed from the outer surface of the housing. Accordingly, the radiation and cooling of the semiconductor switching devices can be efficiently effected collectively.
For example, an arrangement can be provided such that the power distributing unit is provided with a drain connection plate on which the semiconductor switching devices are mounted in a state in which the drain connection plate is electrically connected to the input terminal of the power distributing unit and input-side energizing terminals of the semiconductor switching devices are electrically connected to the drain connection plate, and the radiating member is connected to the drain connection plate in such a manner as to be capable of transferring heat. If such an arrangement is provided, the input-side energizing terminals of the semiconductor switching devices can be electrically connected collectively to the common input terminals by using the drain connection plate, and the radiating member exposed on the outer surface of the housing can be thermally connected collectively. Accordingly, simplification of the circuit configuration and highly efficient cooling can be realized with a simple structure.
Here, as for the drain connection plate, it suffices if the drain connection plate can be electrically connected to the input terminal, and the two members may be formed of separate members and may be mechanically and electrically connected by welding, for instance. However, if the input terminal and the drain connecting terminal are formed of one and the same metal plate, the structure of the electric junction box for a vehicle can be made further compact and thin by further reducing the number of component parts.
In the invention, the specific structure for connecting the output terminals of the power distributing unit and the bus bar circuit unit can be variously set. For example, in a case where the bus bar circuit unit is formed by alternately superposing each of groups of the bus bars and each of the insulating plates in a plurality of layers, the bus bars in a lowermost surface of the bus bar circuit unit are exposed. Accordingly, as the output terminals of the power distributing unit are connected to some of the bus bar circuits, linkage can be established between the power distributing unit and the bus bar circuit unit with a simple structure.
The output terminals of the power distributing unit and some of the bus bars may be connected by, for instance, wire bonding, but if the structure provided is such that they are connected in a state of being directly superposed, more reliable connection can be obtained. In addition, simple means such as welding can be adopted, thereby making it possible to ensure sufficient mechanical strength of the connected portions.
In addition, an arrangement may be provided such that the output terminals of the power distributing unit are arrayed in one direction in a state of projecting in a same direction, while a plurality of power-distributing-unit connecting bus bars are arrayed in a peripheral edge portion of the bus bar circuit unit in a direction parallel to the direction of array of the output terminals, such that the power distributing unit and the bus bar circuit unit are disposed at mutually adjacent positions in a state in which the bus bars and the output terminals are connected to each other. If this arrangement is adopted, the output terminals of the power distributing unit and the bus bars of the bus bar circuit unit can be connected by shortest routs, and the power distributing unit and the bus bar circuit unit can be accommodated in the housing in a compact form.
Further, if an arrangement is provided such that the semiconductor switching devices are arrayed in a direction parallel to the direction of array of the output terminals in the power distributing unit, and output-side energizing terminals of the semiconductor switching devices are directly connected to the output terminals, the power distributing unit itself can be also made compact.
Furthermore, an arrangement may be provided such that not only the output terminals but the output terminals and the input terminal of the power distributing unit are arrayed in one direction in a state of projecting in the same direction, while the plurality of power-distributing-unit connecting bus bars are arrayed in the peripheral edge portion of the bus bar circuit unit in the direction parallel to the direction of array of the output terminals and the input terminal, and as the bus bars are connected to the output terminals and the input terminal, the input terminal is connected to the power source through the bus bar circuit unit. If this arrangement is adopted, all the input and output between the power distributing unit and the external circuits can be collectively effected through the bus bar circuit unit. Hence, the circuitry can be rationalized, and the power distributing unit itself can be made further compact.
With this electric junction box, a circuit for controlling the current ON/OFF of the semiconductor switching devices is required, but the place where this circuit is disposed can be set variously, and may be disposed in the power distributing unit or may be disposed at other places. For example, in a case where a control circuit board which is connected to external vehicle-mounted electronic units through the bus bar circuit unit is incorporated in the housing, if an switching control circuit which is electrically connected to switching controlling terminals of the semiconductor switching devices of the power distributing unit to control the switching of the semiconductor switching devices is incorporated in the control circuit board, it is possible to control the switching of the semiconductor switching devices with a simple structure without especially adding a circuit board for switching control.
Furthermore, the switching control circuit of the control circuit board and the switching control terminals of the semiconductor switching devices provided in the power distributing unit may be electrically connected through the bus bar circuit unit. By the effective use of such a bus bar circuit unit, the structure for connection between the switching control circuit and the power distributing unit can be simplified.
Specifically, an arrangement may be provided such that controlling terminals which are connected to the switching control terminals of the semiconductor switching devices are provided in the power distributing unit, and the controlling terminals and the output terminals are arrayed in one direction in a state in which each of the controlling terminals and each of the output terminals are alternately arranged and project in a same direction, while a plurality of power-distributing-unit connecting bus bars are arrayed in a peripheral edge portion of the bus bar circuit unit in a direction parallel to the direction of array of the output terminals and the controlling terminals, such that the power distributing unit and the bus bar circuit unit are disposed at mutually adjacent positions in a state in which the bus bars are connected to the output terminals and the controlling terminals. By adopting such an arrangement, it is possible to accurately effect connection between the switching control terminals and the output-side energizing terminals of the semiconductor switching devices on the one hand, and the bus bar circuit unit on the other hand, while making the overall electric junction box compact by the adjacent arrangement.
In addition, if the control circuit board is disposed in a state of being substantially parallel to a direction of array of the power distributing unit and the bus bar circuit unit, the electric junction box can be made further compact.
In this case, an arrangement may be made such that the control circuit board is disposed such that at least a portion of the control circuit board overlaps the power distributing unit (i.e., the control circuit board is disposed close to the power distributing unit), and a board accommodating portion for accommodating the control circuit board and a connector portion for connecting the bus bar circuit unit to external circuits are formed in a juxtaposed manner in the housing. If this arrangement is adopted, the space for accommodating the control circuit board and the space for disposing the connector portion can be arranged rationally, thereby making it possible to make the electric junction box further compact.
In addition, an arrangement may be provided such that the semiconductor switching devices are arrayed in a direction parallel to the direction of array of the output terminals and the controlling terminals, and output-side energizing terminals and the switching control terminals of the semiconductor switching devices are respectively directly connected to the output terminals and the controlling terminals. If this arrangement is adopted, the power distributing unit itself can be made compact.
In the invention, although the specific layout of the terminals in the power distributing unit is not particularly restricted, if the terminals are formed of a metal plate and are arranged in a substantially identical plane, the thickness of the power distributing unit can be made very small, which in turn can contribute to the compact and thin size of the entire electric junction box.
It should be noted that the phase that the xe2x80x9cterminals are arranged in a substantially identical planexe2x80x9d is not necessarily to be construed as limiting the terminals to those in which the entire portions of all the terminals are arranged in the identical plane, i.e., all the terminals are planar, but is to be construed to include those in which the input terminal or the output terminals have a shape in which they partially deviate from the xe2x80x9cidentical plane.xe2x80x9d For example, the terminals may be of such a shape that tabs for connection are formed by bending a portion or portions of the input terminal or output terminals which are basically arranged in the identical plane, or end portions of the terminals project in a plurality of rows.
Furthermore, the terminals may be integrally formed by resin molding, and if a power distributing unit housing is formed by this resin molding, the arrangement of the terminals can be reliably fixed with a structure having a small number of component parts.
Moreover, according to a second aspect of the invention, there is provided a terminal mounted on an electric wiring board having a wire circuit formed by a covered wire and a printed circuit formed by a printed conductor, characterized by comprising: a connecting portion capable of electrically connecting an internal circuit of said electric wiring board to an external circuit; a lead portion capable of being electrically connected to said printed circuit of said electric wiring board; and a press-fitting portion capable of being electrically connected to said wire circuit of said electric wiring board, wherein said connecting portion, said lead portion, and said press-fitting portion are formed integrally.
Moreover, according to a third aspect of the invention, there is provided an electric junction box including a housing mounted in a vehicle, an electric wiring board accommodated in said housing and having internal circuits, and connection ports for connecting external circuits to said internal circuits of said electric wiring board, in which each of said internal circuits has a wire circuit formed by a covered wire and a printed circuit formed by a printed conductor, characterized in that said lead portion and said press-fitting portion of each of said terminals according to claim 1 are selectively connected to said printed circuit and said wire circuit, respectively, to allow said connecting portion of said terminal to be connected to said external circuit.
In the invention, the connecting portion which is connected to an external circuit (electronic component) is provided integrally with the lead portion and the press-fitting portion, and electrically conducts with respect to the lead portion and the press-fitting portion. Therefore, the external circuits (connectors, fuses, and the like) can be selectively connected to the printed circuits electrically connected to the lead portions and the covered wires which are electrically connected to the press-fitting portions. Consequently, the covered wire can be connected to the printed circuit located immediately therebelow, thereby making it possible to obtain a more versatile wiring form.
The connecting portion in terms of its form may form a male terminal in the same way as a bus bar tab, or may form a female terminal such as a fuse terminal.
The press-fitting portion in terms of its form is formed in a U-shape, such that the covered wire is pressed into its opening to press open a covering portion of that covered wire so as to connect the internal core to edges at the opening. The opening may be upwardly oriented or downwardly oriented.
The phrase xe2x80x9cexternal circuitxe2x80x9d referred to in the invention is a concept which includes a flat fuse, a relay, and the like and includes a terminal provided in a connector of a wire harness connected to the electric junction box. Further, the phrase xe2x80x9cselectively connectedxe2x80x9d means a form in which a printed circuit and a covered wire, an external circuit and a printed circuit, or an external circuit and a covered wire are connected.
In a preferred form, said electric wiring board includes a printed circuit board for forming said printed circuits and a wire circuit board mounted on said printed circuit board to form said wire circuits, and said terminals are fixed to said wire circuit board.
If this arrangement is provided, the terminals can be arranged in order on, for instance, the upper surface of the wire circuit board, so that there is an advantage in that the alignment of the terminals can be effected easily.
In another preferred form, said terminal connects said covered wire of said wire circuit board and said printed circuit formed on said printed circuit board.
If this arrangement is adopted, the printed circuit formed immediately below the covered wire can be connected to the covered wire, thereby making it possible to obtain a shorter wiring form.
The electric junction box in accordance with still another preferred form further comprises: a load supporting member whereby a connecting load acting on said terminal from a connector of the external circuit at the time of insertion of the connector is supported by said housing.
If this arrangement is adopted, an external force can be received by the housing through the wire circuit board, an excess stress is prevented from being exerted on the printed circuit board with the wire circuit board mounted thereon, making it possible to suppress solder cracks.